[Bug] IE11 can not display box-shadow correctly

[extralam]

in js Line 345 _renderDataSourceDay

we use
for(var i = 0; i < events.length; i++)
instead of
for(var i in events)

other references topic on IE11
https://stackoverflow.com/questions/44390300/for-in-loop-in-ie11

following code updated

case 'border':
					var weight = 0;
					if(events.length == 1) {
						weight = 4;
					}
					else if(events.length <= 3) {
						weight = 2;
					}
					else {
						elt.parent().css('box-shadow', 'inset 0 -4px 0 0 black');
					}
					if(weight > 0)
					{
						var boxShadow = '';
						for(var i = 0; i < events.length; i++){
							if(boxShadow != '') {
								boxShadow += ",";
							}
							boxShadow += 'inset 0 -' + (parseInt(i) + 1) * weight + 'px 0 0 ' + events[i].color;
						}
						elt.parent().css('box-shadow', boxShadow);
					}
					break;